Mucuna macrocarpa is distinctive in its leaves usually without persistent stipels, flowers usually bicolored with conspicuously pubes­cent petal margins at apex, and legume large and linear with thickened but unwinged margin. It is often confused in fruit with M. sempervirens, which differs by its indumentum sparse, pale; flowers not pubescent at their apex; and fruit with finer, more regular, reticulate surface pat­terning and a distinct rounded margin along both sutures. Mucuna bo­dinieri also has similar flowers and fruit but differs markedly by its rounded leaflets with dense pale indumentum. Large-flowered forms of M. macrocarpa with persistent stipels can be confused in flower with M. macrobotrys, which is distinguished by the uniformly purple corolla, wings often relatively broader, and standard often shorter relative to keel. Mucuna "sp. B" of Wilmot-Dear (Kew Bull. 39: 39. 1984) is a variant of M. macrocarpa.